Differential scanning calorimetry and polarizing optical microscope were used to characterize the melting behavior and isothermal crystallization kinetics of pure poly(lactide) and blends of PLA with nucleating agents at varying isothermal crystallization temperatures. Two small crystallization exothermic peak were observed prior to the major melting endothermic peak in the heating scans. This phenomenon occurred lower 10 ℃ in PLA/Talc blends. All nucleating agents increased the crystallization rate of PLA, but Talc was the most effective one. With Talc, at 125 ℃, t _1/2 from 7.78 min to 3.33 min, tmax from 7.84 min to 3.18 min; at 130 ℃,10 min,degree of crystallinity improved 19%.The nucleation mechanism and geometry of crystal growth of PLA and its blends are same.